High-order dispersion suppression for FFAG-based optics

The resurgence of interest in FFAG type magnets has motivated the desire for high-order dispersion suppression to aid the development of dispersion-free straight sections to currently circular designs. In scaling FFAGs, dispersion suppression can only be achieved over a limited momentum range and breaks down as high-order chromatic aberration terms become significant. However by breaking the scaling law and varying the individual multipole components, these can be compensated for and a design for high-order dispersion suppression achieved. This paper presents a process for doing so and discusses the impact on beta functions, as well as the effect of magnet positioning errors.